National Repository of Grey Literature 24 records found  beginprevious15 - 24  jump to record: Search took 0.00 seconds. 
Changes in chemical composition of surface water at the model catchment Lesni potok during the spring snowmelt 2009
Navrátil, Tomáš ; Dobešová, Irena ; Rohovec, Jan ; Buchtová, Jana
Changes of surface water chemistry during the spring snowmelt were evaluated at the forested experimental catchment Lesni Potok found in National Reservation Area Voděradské bučiny. The pH value of surface waters decreased and together with high discharge it launched changes of solutes concentrations. As a good indicator of groundwater in the discharge were evaluated concentrations of Si and isotopic signature of 18O-H2O. The concentration of the main anion SO42- in waters of Lesni potok oscillated during the spring snowmelt in dependence of ratio between melting snow, soil solution, precipitation and groundwater. During the period of increased penetration of surface soil horizons with the water from melting snow causing the increase of DOC concentrations. Concentrations of DOC determined the export of total Fe. Concentrations of Al with DOC did not correlate because the driving factor on concentrations of Al at Lesni Potok is the surface water pH. Concentrations of NO3- were rapidly decreasing during the snowmelt and at the end of this episodic event NO3- concentrations were trivial due to the rapid flushing of soil horizons.
Mercury Speciation Analysis on Model Samples
Rohovec, Jan ; Hojdová, Maria ; Navrátil, Tomáš
Mercury speciation on model samples of iron oxyhydroxides, aluminum oxyhydroxides and layered materials (montmorillonite) was studied using ICP-EOS-TD technique. The TD curves obtainedare used for interpretation of data measured on real samples.
Mercury speciation in forest soils
Hojdová, Maria ; Rohovec, Jan ; Navrátil, Tomáš
We compared distribution of Hg in soil profiles with different level of Hg content in forest floor humus. Detailed study of soil profiles revealed that at the locality with lower Hg content in humus was higher Hg content in mineral horizons in comparison to locality with higher content in organic horizons. Most of the Hg in forest soils was bound to organic matter.
The comparison of geochemical characteristics of Fe, Co, Ni
Kubínová, Petra ; Skřivan, Petr ; Navrátil, Tomáš ; Rohovec, Jan
The purpose of this paper is to compare the geochemical characteristics of iron, manganese, nickel and cobalt. In addition, the evaluation of the main fluxes of the selected elements in the model catchment is made.
Mercury content and speciation in contaminated soils
Hojdová, Maria ; Rohovec, Jan ; Navrátil, Tomáš
The study deals with the determination of Hg distribution and speciation in soils with different level of contamination in the CR. The highest concentrations of Hg were found in topsoil horizons and declined with increasing depth and decreasing content of humus. Thermodesorption analysis distinguished Hg2+ weakly bound to clay minerals from Hg bound to organic matter or sulfides.
Distribution of the rare earth elements in the small catchment Lesní potok
Špičková, Jitka ; Navrátil, Tomáš ; Skřivan, Petr ; Rohovec, Jan ; Mihajlevič, M.
Lanthanides (REE) are particularly useful as tracers of natural processes such as crust and mantle processes, weathering, sedimentary processes, geochemical processes in surface and groundwaters and transport of particulate material through the atmosphere. The aim of this study was to contribute to explanation of the REE cycling by evaluating their concentration in particular components of the ecosystem and by comparing their distributions between these components.

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